Holding back/ missfire and flashing EML under load

Jimny with G13B engine, whilst sitting still it will run, idle and rev perfectly. Take it a run and it immediately holds back and flashes the engine management light. It will do this for a few seconds then be ok again, but does it time after time.

For some reason i cannot communicate with it using Snap on Solus Pro, or a more basic code reader, so im left guessing with no live data!

If i unplug the Throttle position sensor it drives perfect (with EML on constant- so in limp mode?)

From what i can see its a pretty basic engine, with only throttle position sensor, MAP sensor, cam sensor and 02 sensor?

Ive unplugged 02 sensor and it still runs the exact same, changed cam sensor, changed throttle position sensor.

Only thing i havent changed is MAP sensor, im trying to get one. Made harder by the fact no local scrap yard has a Jimny so i have to wait days on parts to 'try'!! Frustrating.

Does anyone know what the ECU relies on whilst in limp mode, purely cam sensor id imagine? Still leaving me with a possibility of the MAP sensor.

Anyone got lots of experience in the engine on these little things???

So TPS wasn't at fault then.

Is the car so hard our soft top? Soft tops usually have a crank sensor too.

Split hose anywhere? Coil pack or lead?

All stuff you have probably tried though I guess?

I havent received/ tried your TPS yet, i managed to make what i think is a good one out of my old one and a Toyota one i bought off Ebay out of curiosity as to whether it was the same. Ill try your when it arrives, though im sure it isnt that now as problem is exact same with different TPS fitted.

Its a hard top with no crank sensor that i can see.

Cant be a coil pack or lead, as it runs perfect with TPS disconnected. Not a split hose kind of fault i dont think, its just passed MOT with good emissions and doesnt have usual air leak symptoms, although ill check to be sure.

If the EOBD worked it would help!

does this help?
www. rhinopower. org /diag / cel.html

Spaces in the link so spam filter doesn't get upset

Lack of go under load is one of the signs of a blocked catalyst. However, the eml doesn't usually come on.

Cheers.

Catalytic convertor, spark plugs, leads, coils, injectors and anything mechanical can be ruled out due to the fact it runs perfectly when on 'limp home' mode. That obviously means all the basics work fine!

It has only just passed emissions for mot, so lambda sensor must be working. (Problem still there with lambda unplugged too)

Swapped cam sensor and throttle position sensor.

Surely only thing left is map sensor?

does this help?
www.rhinopower.org/diag/cel.html

Hi
Have you had any luck? I'm experiencing the exact same problem with my 2001 soft top Jimny with a G13BB engine. Got codes 31 and 32 from the OBD.

Took it into the dealership and typically on the test drive the CEL didn't show up and when they used their own OBD there was no code, they're saying the previous guy must have cleared the memory.

But of course on the drive home the CEL came on and the lack of power that accompanies with it. I need to lift my foot off the accelerator slightly for it to go out and power to come back. But then almost straight away it comes back on again. Seems to be worse when going uphill and after a long drive/driving around all day.

I'm hoping you've found a solution!

cheers

I tried swapping the MAP sensor from a mate's car and still had the same problem. Didn't disconnect the negative before swapping, would this be an issue? I didn't realise you had to.

map sensor could be a possibility lagunas do much the same when there half buggered

also could be a mass air flow sensor or egr valve if fitted?to jimnys ?

what might be a good try (works with citreon c3's ) simply disconnect battery for half an hour and reconnect



hope this helps just thinking aloud without seeing the car

Hi guys,

What you have here is quite a simple fault, You have unknowingly made it more complicated.

You have either a plug or HT/coil breaking down under load, I have seen this so many times on many different types of vehicles.

If you could read the DTC's it would be easier and indicate a code like PO301 (Cylinder number 1 miss-fire) for example, that would lead you straight to the correct faulty cylinder

Since you can communicate with the ECU it will have to be process of elimination, id change the plugs first even if they are not that old, I have fitted brand new plugs which have given this symptom before, if that fails, set of leads,of if you have coils, you can either buy a new set or just bu one, fit it to number 1 cylinder and try it, if it doesn't cure it move it to number 2 cylinder etc, until you cure the problem resulting in that cylinder being faulty.

Mass air flow sensors and MAP sensors don't really cause miss fires or premature detention witch is what is happening when the MIL light FLASHES, they do and can cause poor performance, idle issues and starting problems.

Steve.

Result! According to the mechanic i saw today, the engine wasn't misfiring. He still thought it must be the MAP sensor and recommended I leave it for a day for them to run tests. Anyway, I mentioned some of the suggestions i gained from this website and others and that got him thinking at least, they sometimes need a nudge these guys.

We disconnected the tube that runs from the filter/non return valve (orange box) to the MAP sensor on the sensor end and ran the engine for a couple of minutes, then shut down and replaced it. Problem solved. The tube must have been partially blocked. I saw somewhere that someone else did the same thing which solved the problem.

Hope this helps!

Cheers